This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2001-230502, filed Jul. 30, 2001; and No. 2001-380619, filed Dec. 13, 2001, the entire contents of both of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to a liquid crystal display (LCD) apparatus, and more particularly to a reflection type liquid crystal display apparatus having a front light.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2000-284706, for instance, discloses a conventional LCD apparatus, which is a reflection type LCD apparatus having a front light as an auxiliary light source on a front face side of a reflection liquid crystal (LC) panel.
This reflection type LCD apparatus has a structure as shown in FIG. 10. A reflection type LC panel 11 is constructed such that a liquid crystal layer is interposed between a pair of substrates each having a thickness of 1 mm or less. One of the substrates has an integrally attached polarizing plate 12 on a front face side thereof. A flexible printed wiring board 13 is connected to the LC panel 11. The wiring board 13 supplies the LC panel 11 with electric signals and electric energy for driving the LC panel 11. The LC panel 11 is supplied with electric signals and electric energy from the printed wiring board 13, thereby displaying a desired image on a surface portion thereof.
A front light unit 15 comprises a light guide body 16 and a light source 17 provided on a side face of the light guide body 16. The light guide body 16 has a front surface provided with prism surface, and a back surface coated with an antireflective material. A flexible printed wiring board 18 is connected to the light source 17. The light source 17 is supplied with electric energy from the wiring board 18 and thus emits light. The light guide body 16 of front light unit 15 is fixed by one through four adhesive double-coated tapes 20 disposed on peripheral portions of the polarizing plate 12 of LC panel 11.
The LC panel 11, to which the front light unit 15 is integrally attached, is stored in a cell case 21. The LC panel 11 is integrally attached to the cell case 21 by one through four adhesive double-coated tapes 22 disposed within the cell case 21, and thus a module of these structural elements is formed. Claws 23 formed on the back face of the cell case 21 are used for fixation to a mobile phone or a portable information terminal (not shown).
In the LCD apparatus with the above structure, however, the light guide body 16 has to be directly held by a worker when the front light unit 15 is to be fixed to the surface portion of the LC panel 11 by the adhesive double-coated tapes 20. A problem may occur when the worker touches the light guide body 16, and the productivity of front light unit 15 may deteriorate.
Besides, there are gaps between the front light unit 15 and LC panel 11 at regions not surrounded by the double-coated tapes 20. Dust may easily enter through such gaps. If dust has entered, it is difficult to separate the front light unit 15 and LC panel 11 which are directly adhered. Consequently, dust may not be removed and the productivity of the LCD apparatus may deteriorate.
As shown in FIGS. 11 and 12, the light source 17 of front light unit 15 comprises a light guide stick 25 disposed at one end of the light guide body 16, and a holder 26 which holds the light guide stick 25 and light guide body 16 as one piece. Light-emitting diodes (LEDs) 27 are disposed on both sides of the light guide stick 25 and mounted at both side portions of the printed wiring board 18 fixed on an outside face of the holder 26 by means of an adhesive double-coated tape 28. Light emanating from light emission faces 27a of LEDs 27 enters end faces of the light guide stick 25, which are opposed to the light emission faces 27a. Then, light emitted from the light guide stick 25 enters one end face of the light guide body 16. Thus, the light guide body 16 emits light.
The light guide stick 25 is simply held by the holder 26 and is not fixed. As a result, the positional relationship between the light guide stick 25 and light guide body 16 tends to vary, and the efficiency of light incidence from the light guide stick 25 to the light guide body 16 may deteriorate.
In addition, the double-coated tape 28 and holder 26 are interposed between the printed wiring board 18, on which the LEDs 27 are mounted, and the light guide stick 25. Thus, there is a difference a in dimension between the center axis of the light emission face 27a of each LED 27 and the center axis of the end face of the light guide stick 25. Consequently, the efficiency of light incidence from the LEDs 27 to the light guide stick 25 decreases and the loss in light increases.
Furthermore, the location of each LED 27 on the printed wiring board 18 is not exactly determined and is variable. It is thus necessary to provide relatively large gaps b and c between the light emission faces 27a of LEDs 27, on the one hand, and the end faces of the light guide stick 25, on the other. However, if the gaps b and c are great, the efficiency of light incidence from the LEDs 27 to the light guide stick 25 decreases and the loss in light increases.
As has been described above, with the conventional LCD apparatus, the productivity of the front light unit 15 may decrease, and the efficiency of light incidence from the LEDs 27 to the light guide body 16 may decrease. Owing to such problems of the front light unit 15, the productivity of the LCD apparatus may decrease.
The present invention has been made to solve the above problems, and its object is to provide a liquid crystal display apparatus wherein a problem will hardly occur in a front light unit, contributing to an increase in productivity.
According to an aspect of the invention, there is provided a liquid crystal display apparatus including:
a liquid crystal panel in which a liquid crystal layer is interposed between a pair of substrates;
a front light unit that illuminates the liquid crystal panel; and
a cell case that cooperates with the front light unit to sandwich the liquid crystal panel,
wherein the front light unit comprises a light source section, a plate-shaped light guide body that guides light from the light source section to the liquid crystal panel, and a frame-shaped protection member mounted on a peripheral portion of the light guide body and engaged with the cell case, integrally holding the liquid crystal panel and the light guide body.
According to this LCD apparatus, the frame-shaped protection member is attached to the peripheral portion of the light guide body, and the liquid crystal panel is disposed between the protection member and the cell case. In this state, the protection member is engaged with the cell case, whereby the liquid crystal panel and the light guide body are integrally held. Thus, at the time of fabrication, a manufacturing worker can handle the front light unit by holding the protection member, without directly touching the light guide body. Therefore, problems hardly occur with the front light unit, and the productivity increases.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.